Stellar Spectra in the H Band

Volume 31 number 2 (2003)

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Robert F. Wing

Department

Uffe G. Jorgensen

Abstract

The H band is a region of the infrared centered at wavelength 1.65 microns in a clear window between atmospheric absorption bands. Cool stars such as Mira variables are brightest in this band, and the amplitudes of the light curves of Miras are typically 5 times smaller in H than in V. Since the AAVSO is currently exploring the possibility of distributing H-band photometers to interested members, it is of interest to examine the stellar spectra that these photometers would measure. In most red giant stars, the strongest spectral features in the H band are a set of absorption bands due to the CO molecule. Theoretical spectra calculated from model atmospheres are used to illustrate the pronounced flux peak in H which persists over a wide range of temperature. The models also show that the light in the H band emerges from deeper layers of the star's atmosphere than the light in any other band.